Hey guys, got my head rebuilt about 10 months ago and ever since it's been blowing smoke on start up and now it's doing it all the time at idle. I'm thinking of doing the valve stem seals and also the valve guides, my question is can you do valve guides in the "backyard" sort of thing?

 

I have a bit of mechanical experience but need to make sure that I get the right tools and also if the guides even need doing.

 

Cheers in advance.

 

Oh, the rest of the engine has been fully rebuilt from the rear crank seal to the seals in the carby so just in case anyone questions that part.

Edited December 9, 201015 yr by jono1986

its a head off job. have a look at this video, he gives you a good idea how its done

 

 

while were on topic for smoke. what will cause a 5k to blow smoke on take off after its been idling for a while?

Exactly that! Worn valve stem seals will allow oil to be sucked down the inlet stems at idle and over-run, and it clears as you open the throttle and smokes out the exhaust.

 

You can replace seals without taking the head off, but it takes a trick to keep the valve up while you take the springs off. If you're successful in not dropping a valve into a cylinder its a fast and simple job.

 

You can hook an airhose up to a cylinder and pressurise it to keep the valves closed, or you can try a bent wire over the top of a piston at TDC to hold the valve up.

or another good trick is to feed rope (yes rope) inside the spark plug hole and turn the motor over till it goes hard, the piston will be pushing up on the rope that will be holding the valve closed

 

note - keep one end of the rope out

Thanks for the replies, have seen a youtube video of a guy using the compressed air trick. Might try that tomorrow and run it for a while, hopefully it's only the stem seals that need doing and not the guides.

 

The gregory's manual doesn't say much about all fancy equipment, just says to break off the upper half of the valve guide using a soft drift, then remove the guide through the combustion side of the head using an extractor. Still have to use a reamer but no heavy machinery.

lol Evan- that's clever!!

or another good trick is to feed rope (yes rope) inside the spark plug hole and turn the motor over till it goes hard, the piston will be pushing up on the rope that will be holding the valve closed

 

note - keep one end of the rope out

 

+1 rep to you, only ever used air but that seems like a fairly good idea if you don't have a leak down kit.

haha i love the rope idea. thats brilliant.

 

also if the head was "rebuilt 10months ago" shouldnt they have done the valve stem seals then?

You don't need a leakdown kit if you have a welder. I smashed a sparkplug up and gutted the threaded section, then we welded a small piece of tube into the centre of the sparkplug. Total cost = $0 and the hardest part was actually smashing the guts out of the sparkplug.

 

By the way, you can buy the tool if you can't be bothered.

 

I reckon T&E tolols make one.

 

http://www.tetools.com/catalogue.html

Edited November 7, 201015 yr by philbey

haha i love the rope idea. thats brilliant.

 

also if the head was "rebuilt 10months ago" shouldnt they have done the valve stem seals then?

 

Yeah which is the reason I'm pissed off about the whole thing, did the most of the rebuild myself apart from the head. And now I have to do the stem seals.

Hey guys, haven't actually got round to doing this but now that I have a job I'm looking into the future sorta thing. I want to take the head down to API (engine rebuilders) as soon as possible but am thinking of putting a 5k in it soon anyway, is it a good idea to get worked done to my current 3k head (which has had worked done to it before) or would it be better to do the work on a 5k head?

 

I know they are interchangeable but would like some clarification.

5k block with a 3k head will lower the compression. perfect if you want to turbo/supercharge it but your sticking to N/A just work the 5k head :y:

 

 

edit - work the 5k. the 300mls of capacity is defiantly noticeable and will pull harder than your 3k ever would!

Edited December 8, 201015 yr by Evan G

Supercharging is lingering in my head so what your saying is ticking the boxes :yes:

I reckon T&E tolols make one.

 

http://www.tetools.com/catalogue.html

Yep :yes: part no.4418 "14 & 18mm Air hold fitting set"

Times like these i wish i was still at my old job.

Supercharging is lingering in my head so what your saying is ticking the boxes :yes:

 

Noticed you've said that before. Don't be tempted to build the 5k with a 3k head and run it NA until you fit a charger. The low compression will make it an absolute pig to drive. I've blown a cooler pipe off once and with no boost I reckon I had less power than a stocko 4kc.

 

You could however build the 5k bottom end and then just slap a stock 5k head on it with the hydros. Then over time you can collect some solid lifter conversion parts, and a charger and work your 3k head. Then just fit everything over a weekend or so and boost your way to work on Monday!!!

 

BTW, is the 3k a normal one or a big port? If its a big port then they have the shitty old valve stem seal o-rings. Pro of this is after removing the "engine hat" you can do them all in under 1 minute as you don't have to remove the springs and retainers like the better stem seals.